Sewing machine

ABSTRACT

Sewing machine, here illustrated as a machine for simultaneously embroidering a plurality of pieces of goods with an identical pattern or for embroidering a plurality of identical patterns on a single piece of goods. The illustrative machine comprises a plurality of embroidering stations, a plurality of embroidering mechanisms each of which is disposed at a respective embroidering station, and means for traversing the goods relative to the mechanisms at the stations to embroider the goods in accordance with the pattern.

United States Patent 1191 Schmedding et a1. Jan. 8, 1974 SEWING MACHINE 3,168,881 2/1965 1 Morin 112/2191: [75] Inventors: Albert A. Schmedding; Ernest L. FOREIGN PATENTS OR APPLICATIONS Grade", 777,654 12/1934 France 1. 112/219 A 964,305 7/1964 Great Britain... 112/219 A [73] Ass'gnee' i':$: 229,683 10/1963 Austria 112/219 A [22] Filed: 2 1970 Primary Examiner-H. Hampton Hunter 21 App] N 5 7 Attorney-Bauer and Seymour Related U.S. Application Data ABSTRACT v [62] D1v1s1on of Ser. No. 720,632, Aprll 11, 1968, Pat. 35 5 Sewmg machine, here lllustrated as a machine for s1- multaneously embroidering a plurality of pieces of [52] U.S. Cl..,. 112/218 R, 112/155, 112/219 R, goods with an identical pattern or for embroidering a goo 1 1 plurality of identical patterns on a single piece of 51 1111.01 B65h 59/26 The illustrative machine comprises plurality 58 Field of Search." 1 12/219 A, 219 R, 9f embroidering stations, plurality oflembroiderin'g 112 213 200 1 1g V mechanisms each of which is disposed at arespe'ctive embroidering station, and means for traversing the [56] Refer ce Cited goods relative to the mechanisms at the stations to UNITED STATES PATENTS embroider the goods in accordance with the pattern.

9 Claims, 15 Drawing Figures 1/1959 Winz ..ll2/219R PATENTEDJAN 8 I974 sum 1 or 6 Q: i O -Q as E NVENT a ALBERT A. SCHMEDDING BY ERNEST L. PFEIFER TTORNEYS PATENTEU 8 74 SHEET 2 [IF 6 INVENTORS ALBERT A. SCHMEDDING ERNEST L. PFEIFER ATTO EYS PATENTED 8 I974 SHEET 3 [1F 6 INVENTORS ALBERT A. scumsonmc ERNEST L. PFEIFER 5% MW ATT NEYS PATENTEU 81974 3,783,811

' SHEET u 0F 6 M 66 :6 T4 mmw rr 7% I M l q/.4 H III L:

q INVENTORS ALBERT A. SCHMEDDING BY ERNEST L. PFEIFER gamma/d ATTORNEYS PIUENTEU 9 I974 SHEET 5 BF 6 C m 5WD RE OM THE 0 crr 8 ESP V NAL 7 1 EE P. am 5 LR .7 AE lnLl/w Iv; 1 v 4 I l I ll m\ m; M X 2 3} ZJ MM. 6/ w E/ MN -I w, M ZJ 9 m a 5 f .1 9 I H x 4 3 00 M & m A Wm 4 AI.. 5 g m n W 5 z w L 5 2 5 .I 20 I ATTOR Y5 SEWING MACHINE This application is a division of application Ser. No. 720,632, filed Apr. l l 1968, for Sewing Machine, now US. Pat. No. 3,595,188.

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a sewing machine, in the embodiment shown such machine having a plurality of sewing stations. The illustrative machine is adapted'to hold pieces of goods which are to be embroidered simultaneously in the same pattern. At each station there is positioned an embroidering mechanism in the form of a sewing head and associated looper, the goods being traversed relative to the mechanisms by a pantograph device which follows a pattern or template.

2; Description of the Prior Art Prior art multiple head embroidery machines have employed a plurality of aligned heads carrying needle bars, the heads being disposed above respective embroidering stations provided with means for positioning goods to be embroidered. A pattern following device, such as a jacquard control mechanism, is provided for moving the goods at the embroidering stations relative to the heads of the machine.

In such prior machines, the needle bars of the heads have been driven by branch shafts coupled to a common drive shaft which itself is driven from one end and each looper is coupled to its respective needle bar branch-shaft by mechanism housed in ahollow vertical throat or pedestal of the head casting or housing and by its individual variable speed coupling.The load upon the common drive shaft, particularly under. normal conditions which require rapid starting and stoppingof the machine, tends to twist the common drive shaft substantially, so that various ones of theheads may run appreciably out of phase with respect to the other heads. Additionally, the throats or pedestals severely limited the field size or embroidery pattern and interfered with the connection between the pantograph and the hoops or other supports for the goods.

Further, although a clutch has been provided in each of the drive trains from the said common drive shaft to the needle bars, whereby any one of the heads may be disconnected, such clutches have had an operating wheel which is mounted upon and rotates with the needle bar branch shaft within the sewing head which forms a major part of each drive train/Such clutch operating wheels are difficult to grasp and operate when a head is running. I

Prior multiple head sewing machines such as embroidery machines have incorporated thread'tension re sponsive means to stop the entire machine upon the breaking or depletion of a thread being applied by any one sewing mechanism of the machine. Such means, however, has been complicated and prone to failurel No satisfactory means has been provided for indicating which head of the machine has the broken or depleted threadsearching for the broken thread is unduly timeconsuming, since the break in a thread may not be readily apparent.

Prior machines have employed retractable presser or stripper feet which in their lower terminal position lightly engage or are disposed close to the upper surface of the goods being sewed. The present machine incorporates novel means for altering such lower terminal position of the feet, whereby to accommodate the machine to the handling of goods of differentthicknesses. 1

SUMMARY OF THE INVENTION The multiple'head sewing machine of the invention includes improved means-to drive the needle bars and loopers of all of the sewing mechanisms simultaneously from a common drive means, improved individual clutch means for each mechanism to permit the stopping of any desired one of the mechanisms while the machine is in operation, improved thread tension responsive means to stop the entire machine at anadvantageous point in its operating cycle upon the breaking or depletion of a thread being applied by any one sewing mechanism of the machine, novel signalling means to indicate the particular sewing mechanism the thread of which is broken or depleted, and means for raising the stripper foot associated with each head from contact with the goods before the goods is shifted relative to the needle to formthe design being embroidered. The improved means contemplated by the invention for mounting and driving the sewing heads and loopers permits more advantageous mounting of the holders for the goods, the application of larger patterns to larger fields and the embroidering of yard goods and continuous ribbons.

BRIEF DESCRIPTION OF THE DRAWING- The above and further objects and novel features of the invention will more fully appear from the following description when the same is read in connection with the accompanying drawings. It is to be expressely understood, however, that the drawings are for the purpose of illustration only, and are not intended as. a definition of the limits of the invention.

In the drawings, wherein like reference characters refer to like parts throughout the several views,

FIG. 1 is a somewhat simplified view in perspective of an illustrative multiple head embroidery machine in accordance with the invention, only three of the heads of the machine being shown, the'cams and breaker points or contacts operated thereby associated with one of the means for driving the opposite ends of the upper and lowerdrive shafts being omitted for clarity of illustration, and. the means for holding and moving the goods'to be embroidered being.omitted;,

FIG. 2.is a view in end elevation of the upper portion of the machine, the view being'taken in the direction I from left to right in FIG. 1;

FIG. 3 is a view in verticalaxial section through an end of the looper driving shaft, the section being taken along the line 3--3 of FIG. 2, certain of the parts being shown in elevation; t

FIG. 4 isa view in perspective of one of the two variable speed couplings employed to drive the looper drive shaft, portions of the walls of the coupling housing being broken away;

FIG. 5 is a view in perspective of a sewing head of the machine and the part of the table associated therewith, the front cover plate of the head being removed, the needle being shown in raised position near the start of its downward stroke, the view being taken from line 5-5 of FIG. 7, the embroidery station providing means being omitted;v i a FIG. 6 is a view similar to FIG. 5 but with the needle bar'shown later in its downward stroke and with the point of the needle about to enter the goods (not shown) being embroidered;

FIG. 7 is a view in vertical section through a sewing head and an associated looper of the illustrative machine, the section being taken generally along the line 7-7 of FIG. 5, certain of the parts being shown in elevation;

FIG. '8 is a fragmentary view in vertical section through a sewing head, the section being transverse to the length of the head and taken along line 8--8 of FIG.

7 thread break detector, the view being taken in the direction from right to left in FIG. 9;

FIG. 12 is a somewhat schematic view in front elevation of a sewing head in accordance with the invention, the needle being shown as just having started its downward stroke, the thread tension lever being in substantially its uppermost position, and the thread extending between the thread tensioning means on the head and the eye of the needle being under appreciable tension;

FIG. 13 is a view similar to FIG. 12 showing parts of the sewing head in the position which they assume in a later portion of the sewing cycle, the'point of the needle being shown as having descended so as to pass downwardly through the goods (not shown) being embroidered, the thread tension lever being in the upper portion of its downward stroke, and the thread extending between the thread tensioning means on the sewing head and the eye of the needle being in slack condition;

FIG. 14 is a fragmentary view in horizontal section through the clutch of a sewing machine head, the section being taken along the line 14-14 of FIG. 7, certain of the parts being shown in plan; and

FIG. 15 is a diagram of the motor control and thread break detector and signalling circuit which is employed in the disclosed machine of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Turning now to the drawings, there is shown in FIG. 1 a multiple head sewing machine adapted for use with means, which is not shown in FIG. 1 but is schematically shown in FIG. 7, which provides a plurality of embroidery stations one of which is associated with each sewing machine, that is, a sewing head and its associated looper. In such embroidery machine the embroidery station providing means, which'is shown at 13 in FIG. 7, is adapted to support goods to be embroidered. Such means 13 has a plurality of embroidery stations thereon, of which one is schematicaaly shown at 18. The means 13, and thus all of the embroidering stations 18, are moved in unison by a pattern following device which is conventional in the art and is not here shown.

A plurality of similar sewing machine heads are mounted upon a horizontal upper rail 11 which is supported above a main horizontal table 96 by two similar spaced, parallel end supports 12 and 14. Such manner of supporting the sewing heads provides a clear path therebeneath in a direction from the front to the rear of the machine, so that the goods being sewn or'embroidered need not be limited in length. The drive for the sewing heads 10 is provided by an upper main horizontal drive shaft 16 which, as shown, is deposited rear wardly of the rail 11 and passes through a rear lower portion of each of the sewing heads. The vertically reciprocable needle bar 81 of each head is driven by means drivingly connected to shaft 16, such means ineluding a shaft 50 within the housing of each head which is shown more particularly in FIGS. 7 and 14 and will be described hereafter.

The sewing machines shown are of the two-thread, lock stitch type, wherein the sewing heads 10 apply a first, upper or needle thread to the goods, and a looper 107 (FIG. 7) applies a second, lower or under thread thereto. The lock between threads is formed by passing the upper thread around the lower thread and tightening the two threads together in the goods being sewed.

A lower horizontal longitudinally extending shaft 17,

which drives the loopers associated with each of the sewing heads of the machine, is disposed beneath the table of the machine. Shaft 17 is driven at its opposite ends through variable speed couplings 115, the couplings having at their input ends stub shafts 116 which are driven in synchronism with the shaft 16 by Timing belt and sprocket means which areshown more particularly at the left of FIG. 1' and in FIG. 2. Thus at the rear of the machine there is provided a horizontal longitudinally extending lower shaft 15 which is driven by a motor (not there shown) through the medium of a V- belt 20 entrained over .a'pulley 19. At each end of the machine, outwardly of the supporting members 12 and 14, through which the ends of shafts 15, 16, and 116 extend, there is provided identical Timing belt and sprocket driving means which synchronizes the rotation of the shafts l6 and 116 and maintains them accurately inphase. Thus outwardly of support 12 there is a Timing belt 21 which is entrained over sprockets 24, 25, and 26 which are affixed to shafts15, 16, and 11.6, respectively. Outwardly of support 14 there is a Timing belt 21 which is entrained over pulleys 24, 25, and 26 (FIG. 1) which are affixed to shafts 15, 16, and 116, re spectively. Belts 21 may be tensioned by adjustable idle pulleys 27, as shown. By reasonof such driving of the shafts 16, 116, and-17 by shaft 15, the twisting of such shafts under rapid starting and stopping conditions is minimized, whereby the needle bars and loopers of the various sewing machines are maintainedaccurately in phase.

The frame or housing 29 of each sewing head 10 is of generally U-shape in side elevation, as shown in FIGS. 1 and 7. Housing 29, which is hollow and generally downwardly open, has a depending rear skirt 30, a first rear intermediate-rib 31, a second intermediate rib 32, spaced forwardly of rib 31, and a vertical hollow front portion 34 within which the vertically reciprocable needle bar 81 and its driving means are mounted. The upper portion of the rear wall or skirt 30 is thickened at 35 to provide support for a bearing 51, received in a bore in housing portion 35, which supports the rear end of the shaft 50 of the sewing head A portion 36 of wall 30 is of somewhat thinner section. As shown in FIG. 8, the horizontal driving shaft 16 is journalled in a bearing 39 mounted in the housing 29 of the sewing head 10. Such bearing, which is of the type known as a ball bearing, has an outer race .40 which is fixedly held within a bore 37 in a thickened portion 35 of the housing 29 between an inner and an outer spring ring is secured to the shaft as by a pin or Allen screw 45.

Affixed to the shaft 16 within the housing 29 there is a helical gear 46 having a collar 47, the collar being secured to shaft 16 as by a set screw 49 in abutment with spacer'46'. It w'ill'be apparent that with such construction any one of the sewing heads may be removed from the machine upon the loosening of the shaft 16 from each of its bearings 39 and helical gears 46, as well as the removal of the end driving sprockets from the shaft, so that the shaft may be readily withdrawn axially from all of the heads. Following this the desired heads 10 are removedfrm the rail 11, and the shaft 16 with its bearings and helical gears are reassembled within the remaining sewing heads 10, and the shaft 16 is then remounted in supports 12 and 14.

The needle bar driving shaft 50 of each sewing head is rotatably supported at its rear in the above mentioned ball bearing 51 and adjacent its forwardend in a sleeve'bearing 52 which is mounted in a bore in the rib 32 of the housing 29. Meshing with the helical gear 46 on shaft 16 is a second helical gear 54, gear 54 being affixed to a sleeve 55 which is mounted on shaft 50 for rotation with respect thereto. The sleeve 55 and the gear 54 thereon are retained from travel axially with respect to the shaft 50 by spring rings received within annular grooves in the shaft 50 at each end of the sleeve 55. Gear 54 and sleeve 55 are selectively drivingly connected to shaft 50 by a clutch'53, which is 50 forwardly of sleeve 55 is keyed to the shaft for rotation therewith through the medium of a key affixed to the shaft and received within an axially extending groove 59 in the inner surface of the sleeve 57. At one location angularly thereabout the sleeve 59 is provided with a rearwardly open recess 61 which selectively accurately receives the forward end of the eccentric pin 56. It will be seen that the g ear 54 may be drivingly connected to the shaft 50 through the medium of the clutch sleeve 57 in only one angular position of such parts relative to each other. Thus the required phase relationship between the needle bar 81 and the looper 107 of the individual sewing machine is restored when the sleeve 57 is returned was rearward, engaged or driving position, shown in FIG. 7, after having been operated to disconnect the needle bar driving shaft 50 from the shaft 16. v I The sleeve 57 is constantly urged into its rearward, clutch-engaged position, by a coil compression spring 62 which is telescoped about shaft 50 forwardly of the sleeve 57, and which acts between the forward end of sleeve 57 'and an abutment ring 63 affixed to shaft 50, as shown. The clutch sleeve 57 may be shifted axially of the shaft 50 selectively to disengage and engage the clutch by the following means. An annular groove 64 is provided in the outer surface of clutch'sleeve 57, such groove receiving an eccentric projection or pin 67' (FIG. 14) on the inner end of-a clutch operating'cross shaft 65 which is journalled in the housing 29 on one side thereof and extends outwardly,'therethrough-A lever 66 affixed to the outer end of shaft-65 may be thrown in one direction to retract the clutch sleeve 57 ment 70, a connecting rod 87 pivotally secured at its upper'end to the pin 86 and at its lower end to a pivot 6 forwardly against the pressure of spring 62 to disengage the clutch; when such lever 66 is thown in the other direction, the spring 62 thrusts sleeve 57 rearwardly so that pin 56 on sleeve 55 may be received within recess 61 on sleeve 57. For a purpose to more fully appear hereafter, the engagement of pin 67 with the radial wall of groove 64'during clutch disengagement tends to prevent rotation of sleeve 57 and shaft 50.

Mounted upon the rear end of the shaft 50 is a hand wheel 69 by which the needle bar 81 of the head 10 may be manually driven, as for reengaging the clutch,

positioning the needle 91, or as required for servicing or adjustment of the sewing head mechanism. Affixed to the forward end of shaft 50 coaxially thereof and within the portion 34 of the head there is a circular cylindrical element 70 which functions both as a barrel cam for driving a thread tensionlng lever 76 of the sewing head and as a crank for reciprocating the needle bar 81 of the head vertically. Element 70 has a curved parallel sided cam groove 71 in its peripheral surface, such groove receiving a cam follower roller on the outer end of an arm 73 of a bell crank 72 which is mounted for oscillation about a horizontal pivotal support 74 affixed to the frame 29 of the head. The thread tensioning lever 76, which forms the second arm of the bell crank, extends outwardly through a vertical slot 77 in a plate 79 which covers the forward end of the housing 29 of the head. Lever 76 has at its outer end a guiding eye 80 through which the upper thread 145, which is applied by'the sewing head 10, passes in its travel to the needle, as shownin FIGS. 12 and 13'.

i The needle bar 81, which is in the form of a circular rod, is guided at its upper end within a vertical sleeve 82, the upper end of the sleeve being affixed to the upper wall of portion 34 of the housing 29 of the head,

as shown in FIG. 7. The lower portion of the needle bar 81 is guidingly received within a short vertical sleeve 84 coaxial of sleeve 82, sleeve 84 being affixed to a lower forward part 85 of the portion 34 of the housing. Driving connection between the element 70 on shaft 50 and the needle bar 81 is effected by ,an eccentrically mounted crank pin 86 on the forward end ofthe elepin 89 which projects rearwardly from a boss 90 connected to the needle bar. The lower end of the needle bar is provided with a vertical blind bore receiving the upper, shank end of the eedle 91, the needle being retained in such bore by a needle retaining screw 92.

As shown in FIG. 7, the machine has longitudinally extending lower frame members 94 and 95 which extend from end to end thereof and which, with other frame members, not shown, support the table 96. Frame members 94 and 95 are connected at their ends by the lower ends of supports 12 and 14, the lower end of the latter, in which one end of the drive shaft 15 is journalled, being shown in FIG. 7. At an opening 97 through the table 96 in alignment with each of the sewtion 101 of the looper unit frame presents a rectangular opening therethrough which provides access to the bobbin of the looper, such opening being covered by a removable plate 102, the upper surface of which lies flush with the top of the table 96.

A further, fixed cover portion 104, rearwardly of plate 102, is provided with a vertical needle receiving hole 105 therethrough. The lower or under thread is supplied by a bobbin (not shown) disposed within a bobbin holder 106 and is fed to a rotatable looper 107 which is affixed to the forward end of a looper driving shaft 109. The looper 107, which is of conventional construction, has a hook 108 thereon which rotates with the looper 107 and the shaft 109. As is well known in the art, upon the descent of the needle through the goods being sewed, the loop of the upper or needle thread 145 which is formed beneath the goods is taken by the point of the hook 108 on the looper and is passed around the bobbin, which contains the lower or under thread and a tensioning device for such lower thread. At this time, the loop in the needle thread is permitted to enlarge under substantially no tension by the descent of the needle thread take-up lever 76. After the upper thread has been passed about the lower thread, the two threads are tightened together to form a lock stitch.

The looper rotating shaft 109 is mounted for rotation in rear and forward bearings 1 and 111, respectively, in the looper frame, shaft 109 being rotated by the shaft 117 through the medium of meshing helical gears 112 and 114 which are affixed to shafts 17 and 109, respectively. The shafts 109 and the loopers 107 carried thereby of the various sewing machines are all similar and are drivingly connected was to be rotated in synchronism and inphase. In order to rotate the looper of a round bobbin, lock stitch sewing machine at a slower speed when the upper and lower threads were being looped together than during the remainder of the rotation of the looper there was formerly provided a variable speed coupling for each looper, such coupling being interposed in the driving train therefor. In accordance with the present invention, only two variable speed couplings .115 are provided, one at each end of the looper drive shaft 17. This results in a more rugged, trouble free, and economical machine.

Since the two couplings 115 are identical, only one is particularly shown and described. Such variable speed coupling is shown in detail in FIGS. 3 and 4. As there shown, the inner end of a stub shaft 116 which is driven by the Timing belt 21 through the sprocket 26, is mounted for rotation in a sleeve bearing 117 which is mounted in a bore in the lower part of support member 12 and an aligned bore in one side 121 ofa housing 120 for the coupling. The confronting outer end of the looper drive shaft 17 is mounted in a bearing 1 19 in the opposite wall 122 of the housing. Affixed to the inner end of the stub shaft 116, as by being pinned thereto as shown, is a first, longer crank,124 disposed within the 1 housing. A second, shorter crank 125, also within the housing, is affixed to the outer end of the looper drive shaft 17. A link 126 connects the crank pin 127 on crank 124 to the crank pin 129 on crank 125. Such variable speed coupling, which is conventional, is so disposed relative to the shafts 116 and 17 as to drive the looper 107 at a slower'speed as the point or horn 108 thereof approaches, passes by, and leaves the path 8 of the needle 81 than during the remainder of the rotation of the looper.

The sewing machine of the invention is provided with a presser foot which substantially engages the upper surface of the goods being sewed or embroidered from the time the needle enters the goods until the needle is I withdrawn therefrom, thereby functioning to aid in retaining the goods in place and to prevent its substantial rising as the needle is withdrawn from it. Such presser foot, however, is provided with means whereby it is elevated from the goods upon the upward travel of the needle after having been withdrawn therefrom, so that the goods is free for travel in whatever direction is re- 'quired of it by the pattern following mechanism before the next downward stroke of the needle. The presser foot 130 and its operating mechanism are particularly shown in FIGS. 5, 6, and 7.

Stripper foot 130 is formed as an integral lower part of a slide member 131, the upper and intermediate portions of which are straight and are disposed vertically. The upper end of member 131 is provided with a horizontal collar 132 which surrounds and is slidable with respect to the needle bar 81. The lower end of the straight vertical portion of slide 131 is received within a forwardly open shallow vertical groove 134 in the lower portion 85 of the portion 34 of the frame of the sewing head, and is retained therein by the central lower edge portion of the cover plate 79. At its lower end the member 131 is bent rearwardly to form a generally C-shaped portion 135, the upper end of which is horizontal and has a hole 136 therethrough guidingly receiving the lower end of the needle bar 81. Below such C-shaped portion, member 131 is bent vertically and then forwardly to form the horizontal presser foot 130. Such foot has a vertical, needle-receiving hole therethrough, as shown.

Extending sidewardly fromthe collar 132 on slide member 131 is a horizontal arm 137 integral therewith. A coil tension spring 139, which constantly yieldingly urges the slider 131 in a downward direction, has its upper tang secured to the outer end of arm 137 and its lower tang secured to a spring anchoringpin 140 af sewing head inwardly of the cover plate 79. Travel of the slidemember downwardly, however, is limited by its engagement with the boss affixed to the needle bar 81. It will thus be apparent that the slide member 131 travels with the needle bar 81 from the uppermost position of the latter downwardly through the position shown in FIG. 5 and toward the position thereof shown in FIG. 6 wherein the stripper foot lightly engages or is preferably a short distance above the upper surface of the goods 138 being embroidered. As the stripper foot moves downwardly past the position thereof shown in FIG. 5, a laterally extending arm 141 on the slide member engages the upper end of a coil compression spring 142, the lower end of which is affixed to the upper end of a machine screw 144 threaded into the portion 85 of the frame of the head in alignment with the arm 141. Thus as the needle bar descends the slide member 131 travels freely downwardly therewith until the arm 141 engages the upper, end of the spring 142, after which spring 142 progressively opposes the coil tension spring 139. When the force exerted by spring 142 equals that exerted by spring 139, further travel of the slide member 131'downwardly ceases. The screw 14 may be adjusted vertically to determine the termicloth on table 96. Without means to prevent it, the needle and foot would creep to their lowermost positions due to the torsional forces applied to shaft 50 by the pull of tension spring 139 and the drag of continuously rotating gear 54, 55 on shaft 50. The clutch mechanism when in disengaged position functions as a brake to override the above mentioned torsional forces and thus prevents undesired rotation of shaft 50. The braking is effected by the frictional engagement between pin 67 and the radial wall of annular groove 64 under the compression of spring 62.

Each sewing head 10'is provided with its individual upper thread 145 which is fed thereto from a spool or bobbin, not shownfihread 145 pa'ssesthrough a pigtail guide 146 mounted on top of the frame of the head'to a guide roll 147, and then to an adjustable thread tensioning device 149 and is shown as being of the conventional washer type. From the tensioning device 149 the thread 145 travels downwardly through a pigtail guide 151 on a thread break detector means 150, to be described, upwardly to the guiding eye 80 on the thread tensioning lever 76, downwardly to a fixed lower pigtail guiding eye 152 on cover plate 79,, and thence to the eye of the needle 91.

As is conventional with sewing machines of the type shown, when the needle 19 is in its fully elevated position, the thread tensioning lever 76 is in its lowermost position. As the needle starts down, the lever 76 moves rapidly toward its fully elevated position, as shown in FIG. 12, causing the upper thread 145 to become tight in the portion of its run between the tensioning device 149 and the eye of the needle 91. In all other relative positions of the needle and the thread tensioning lever 76 the thread 145 in such run thereof is relatively slack The machine of the invention incorporates means whereby the breakage of a thread both energizes a'signal device associated with the particular fs'ewing machine whose thread has broken, and also'deenergizes the driving means for all of the sewing heads of the machine and quickly brings the sewing machines to a stop. The thread break detector means and the machine controlling elements and circuit associated therewith are shown in FIGS. 2, 9, 10, 11, and 1 5.

As shown in FIG. 12, the pigtail guide 151 of the thread break detector 150 is disposed laterally between and below both the tensioning means 149 and the lever 76. Guide 151 thus forms the thread 145 into a salient or V-shaped run with the guide 151 at the bottom thereof. Guide, 151, which forms a part of the thread break detector, is mounted for resilient deflection upwardly by the unbroken thread 145 when the parts of the sewing machine are in the position shown in FIGS.

l and 12. Guide 151-also forms the upper of two coclosed during all other portions ofthe cycle of the sewing machine. If, however, the thread 145 should break, the contacts associated with the thread break detector remain closed throughout the entire cycle and, as a result, not only energize the above-mentioned signalling device but cause the driving means for the entire machine to be deenergized. I I

The construction of the thread break detector 150 is shown more particularly in FIGS. 9, 10, and 11. As there shown, the detector is mounted upon the cover plate 79 for the head of the machine,'there being a tubular metallic body 153 which projects through an opening in the cover plate and is affixed thereto. The forward end of body 153 is out along a forwardly and downwardly inclined plane. Within the tube 153 there is disposed an electrical insulator 154 having a forward tubular skirt portion and a transverse solid portion 158 at the rear end thereof. The rear end of electrically .conductive'coil spring 155 isaffixed to insulator 154 by being telescoped'within a downwardly and forwardly passing through the guide 151 is slack or substantially untensioned, the guide 151 lies in it lowermostposition inclined bore 160 through the rear portion 158 of the insulator, electrical connection to the rear end of the spring being effected by a conductor 156 which is forcibly embraced by therear end of the spring. Telescoped within the forward end of spring 155 and forcibly'engaged therewith, with its rear end spaced somewhat from the forward end of the conductor 156, is the shank 157 of the electrically conductive pigtail guide 151, the lower surface of which acts as a first, upper contact'of the two cooperating contacts of the threadv break detector. The other, lower contact of the detector is here made in the form of a removable U-shaped clip 159 which is telescop ed over the forward lower edge of the tubular body 153 and makes secure electrical contact therewith. The frame of the sewing machine is grounded, as shown in the circuit diagram in FIG. 15, to be described, so that when the pigtail guide 151 is in its lower position (FIGS. 9 and 11) the conductor 156 is' connected to ground.

As shown, when the thread 145 inthe portion thereof and the contacts of the thread break detector are closed. When, however, such run of the thread 145 is tensioned, the thread pulls the guide 151 upwardly,

thereby to flex" thev spring 155 and to separate the two contacts of'the' detectorJAs above mentioned, should the thread 145 of a sewing headbe broken or depleted when it would otherwise normally be tensioned to se'parate such contacts as shown in FIG. 10, the contacts then engage each other whereby the signalling means 181 associated'with such sewing head is energized and the entire machine is brought to a stop. I p 1 The manner in which such signalling device and the machine controlling circuit operates will be more fully understood upon consideration of FIGS. 2 and 15. As shown in the latter of such figures, the multiple head sewing machine is driven by a motor 164 having a motor shaft 165; shaft 165 is drivingly connected to the lower main driving shaft 15 of the machine by the belt 20 shown in FIGS. 1 and 7. The motor 164 is supplied with operating current from a source L L through the normally open contacts of switches 200 and 201 of a relay C. Itwill be apparent that when the contacts of switches 200 and 201 are closed, the motor 164 willbe gized by source L L through a temporarily manually closed starter switch 202, and the normally closed switch 172 of a relay B. The thus energized coil 203 closes switches 200 and 201, thus energizing the motor, and also closes a switch 204 in a holding circuit which connects said coil across the source through switch 172 independently of starter switch 202. The switches of relay C will accordingly remain closed and the motor energizedv until coil 203 is deenergized by opening a stop switch 205 manually or opening switch 172 in a manner hereinafter described in response to the thread break or depletion detector 150.

As shown in FIG. 15, the control circuit for the machine includes a voltage step-down transformer 167 having a primary winding 169 connected to the current source L L, and a secondary winding 170 which is connected in and powers the control circuit. The control circuit is so constructed and arranged that upon the breaking or depletion of any one of the upper threads 145 being applied by the respective sewing heads of the machine the coil 174 of the relay B is energized by the control circuit, whereby to open the contacts of switch 172 and to stop the motor 164.

A first terminal of the secondary winding 170 of the transformer 167 is connected to ground 206 through a normally closed reset switch 173 mechanically connected to starter switch 202, the one being open when the other is closed. The second terminal of the secondary winding is connected to a first terminal of the coil 174 of relay B. The other end of the relay coil 174 is connected to a first contact of a periodically opened and closed contact set 175. The other, second contact I of such set is connected by a wire 184' to a terminal 194 of a circuit portion 180. Between the seeondvterminal of the secondary winding 170and the relay coil 174 there is connected a wire 190 whichleads to a terminal 195 of the circuit portion 180.

A first contact of a second periodically. 'opened and closed contact set 177 is connected to wire 190, the other contact of such set being connected to a terminal 196 of the circuit portion 180. Although only one circuit portion 180 is shown in FIG. 15, there is actually a plurality of such circuit portions, one for each sewing head 10, the respective terminals 194, 195, and 196 of all said circuit portions being connected in series, so that, as above explained, the breaking of any one thread 145 not only energizes the respective signalling means 181 but also stops the entire machine. Since all of the circuit portions 180 are identical, only one need be described.

A wire 182, which is connected to terminal 196, leads to one fixed contact of a normally closed contact set 188 of a relay A, the other fixed contact of such set being connected through a wire 184 to one terminal of its respective signal light 181 which is mounted upon the front cover plate 79 'of the respective sewing head. The other terminal of signal light 181 is connected by a wire 198 and a normally open switch 207 of relay A to terminal 194. The above described conductor 156 of the thread break detector 150 is connected to wire 198,

as shown.

Also connected to wire 198 through a wire 189 is the first contact of a normally open third contact set 186 of relay A, the other contact of such set being connected directly to ground 208. A normally open fourth set of contacts 187 of relay A has one contact thereof connected to lead 184 and the other contact thereof connected through a wire 199 to terminal 195. The movable contactors of relay A are connected'to move together, but are electrically insulated from each other. Such contactors are raised to close contact sets 186, 207, and 187 and to open contact set 188 when the coil 185 of relay A is energized. One terminal of coil 185 is connected to wire 184 and the other terminal thereof is connected to wire 198.

The cam operated contact sets 175 and 177 are shown more particularly in FIG. 2. Both of such contact sets are here constructed similarly to the low tension breaker points on an automobile, the movable contact of each set being constantly urged toward contact-closed position by a leaf spring, and being opened by a cam acting through a cam follower affixed to the movable contact. In the embodiment shown, the contact sets 175 and 177 are actuated by cams 176 and 179, which are affixed to shafts l6 and 15, respectively,

as shown in FIG. 2. Since .such contact sets are similar,

only set 175 need be specifically described.

An electrically insulating contact supporting member 178 is secured to the outer face of support member 12. The fixed contact of the set is secured to member 178; the movable contact is mounted on one end of an electrically conducting lever arm which is pivotally mounted on member 178, the other end of the lever arm being connected through the pivot means to coil 174. Intermediate the length of the lever arm,there is mounted a cam follower roll 183, which bears upon the rim of the outer flange of sprocket 25, such rim forming the cam 176. The cam 176 is of circularfshape coaxial of shaft 16 throughout its circumference with the exception of a cut out zone 192 wherein the leading end has an abrupt radially inwardly extending shoulder, the

remainder of such zone constituting a ramp, the radius of which progressively increases-untilitreaches the rar dius'ofithe'.remainder'of the cam'at, the trailing end of 177 remains open at all times except during the period when the cam follower is in thecut outv zone of cam 179. The sprocket 24 (and thus the cam 179) is affixed to shaft 15 in such angular position that the contact set 177 is closed during that period in the sewing cycle in which the upper thread is tensioned, as described in connection with FIG. 12, and is open at all other times. The contact set 175 and cam 176 are similarly positioned relative to shaft 16, except that cam 176 is angularly disposed to close contact set 175 a short interval after contact set 177 is closed by cam 179. Both cams are angularly adjustable relative to the driving shafts therefor.

The thread breakage detectors of the respective sewing heads and the control circuits of which they are parts function as follows. When an upper thread 145 of a sewing head 10 is depleted or breaks, the upper contact 151 of the thread detector 150 of such head remains in engagement'with the lower ground contact 159 thereof during that portion of the sewing cycle when such contacts would have been open if the thread were unbroken. As we have seen, the contact set 177 is closed during such portion of the cycle. When'the contacts of the detector 150 are closed at the same time as the contacts of the contact set 177, the signal light 181 of the sewing head whose thread 145 has broken is energized by secondary winding 170 through wire 190, contact set 177, wire 182, contact set 188, and wire 184, and through wires 198 and 156, upper contact 151, the lower ground contact 159' of detector 150, ground return 206 and reset switch 173.

Simultaneously with the energization of the signal light 181, the coil 185 of relay A of the respective cirw cuit portion 180 is energized by current flowing from winding 170 and wire 182 through such coil and to ground 159, 206 through wires 184, and 156 and the contacts of the detector 150. Energization of such relay coil 185 causes the normally open contact sets 'of switches 186, 207, and 187 to close and contact set188 to open. Closed switch l87completes a holding circuit for relay coil 185through wire 190, wire 199, switch 187, wire 184, coil 185, wire 156, and the contacts of detector 150 to ground 206. Such holding circuit bypasses the contact set 177, and thus the relay coil 185 remains energized after the opening of contact set 177 as shaft 15 and cam 179 continue to rotate. An independent direct connection to ground for the signal light 181 and coils 185 and 174 of relays A and B, respectively, is simultaneously established through wire 198, wire 189, and the now closed switches 186 and 207. Such independent connection to ground, which is in parallel with the first mentioned connection to ground at 159 throughthe contacts of the detector 150, carries the greater part of the current required to energize the signal light ,181 and the relay coils 185 and 174, and thus removes any possibility of unduly heating and weakening the current-carrying "spring. 155 of the thread break detector 150 should such signal light and relay coils remain energized for an extended period.

The describedenergization of the relay .coil 185 of any one of the circuit portions 180 andthe closing of its switches 186 and 207 also results in energization of the relay coil 174 whencontact set 175 is subsequently closed. Thus upon the breakage of a thread 145 at any one of the sewing heads 10 of the machine, relay coil scribed in the foregoing specification, it is to be espe-- 174 is energized, whencontact set 175 is closed,

through a circuit from secondary winding 170 of transformer 167 to relay coil 174, contact set 175, wire 184', switch 207, and ground .206 by the above described alternate paths l through wire 189 and switch 186, and (2) through wire 156 and the contacts of the detector 150. The energization of relay coil 174 opens switch 172, thus breaking the holding circuit for relay coil 203 and thereby stopping the motor 164. Relay B remains energized only during the short period during which contacts 175 are closed. Motor 164 is preferably one of the type known as a Unibrake electric motor,

which stops very quickly upon the opening of switches.

200 and 201. The parts of the described machine may be so constructed and arranged that in the event of the breakage of a thread 145 at any of the sewing heads the machine will stop with all of the needle bars 81 of the heads in a raised position to allow rethreading. Timing in this respect may be varied by adjusting the earn 176 tovary'the closing time'of contacts 175. l

Upon the stopping of the machine by the breakage of a thread 145, the lighted signal light 181 will immediately inform the operator which sewing head has the broken thread. The operator then rethreads such sewing head. During this time the relay coil 185 of the sewing head 10 being rethreaded will remain energized through the holding circuit and the signal'light 181 of such head will remain energized. To start motor 164, the start switch 202 is momentarily manually closed, thereby monentarily opening reset switch 173. The circuit break at the latter opens the holding circuit for relay coil 185 and thus deenergizes it, so that switches 186, 207, and 187 are opened and switch 188 is closed, and the previously energized signal light 181 is deenergized. The control and signal circuit is now in its initial, operative or ready condition. The closing of switch 202 reenergizes relay coil 203 and starts the motor as described above.

Although only one embodiment of the invention has been illustrated in the accompanying drawings and decially understood that various changes, such as in the relative dimensions of the parts, materials used, and the like, as well as the suggested manner of use of the apparatus of the invention, may be made therein without departing from the spirit and scope of the invention as will now be apparent to those skilled in the art.

We claim: i

1. The combination with a sewing machine having a reciprocable needle, drive means for cyclically reciproeating said needle, means toguide athread from a supply to the eye of the needle and means to tension the thread between the supply andneedle during only a part of eachcycle of operation of the needle, of control means for automatically rendering said drive means inoperable to reciprocate the needle upon failure of said thread tensioning means. to tension the thread, said control means including a thread tension detector comprising a member having a first end adapted to be secured to a fixed support and an arm extending a substantial distance outwardly from said first end, means forming a first, fixed electrical contact affixed to said arm adjacent the outer end thereof, an electrically insulating body affixed to the first endof themember, an elongated electrically conducting coil spring extending generally parallel to and spaced from said arm, a first terminal means supported on the insulating body to which the first, inner end'of the spring is secured, a thread guide secured to the second, outer end of the spring, and means affixed to the thread guide forming a second, movable contact which engages the first contact when the thread is untensioned, the thread guide being adapted to form a salient zone in the the member is made of electrically conductive metal and is adapted to form a second terminal of the detector, and wherein the first contact is formed as a clip which is removably telescoped over the outer end of said arm.

4. The combination of claim 1 including signal means and means for automatically energizing the signal means upon failure of said thread tensioning means to tension the thread.

5. The combination of claim 1 wherein said control means functions, upon such failure, to effect stoppage of the needle at a predetermined approximate position in its cycle to facilitate rethreading thereof.

6. In a sewing machine having a reciprocable needle, drive means for cyclically reciprocating said needle and means for tensioning a thread between a source and the needle, the combination therewith of an electrical control system comprising a source of electrical energy, a signal circuit connected across said source comprising a first normally closed switch, a second normally open switch, an electro-magnet and a third normally open switch adapted to be opened by said electro-magnet when the same is energized, said switches and electromagnet being connected in series, a fourth normally open switch adapted to be closed by said electromagnet when the same is energized, means for opening said first switch when the thread is under tension, means for momentarily closing the second switch during a portion only of each cycle of operation of the needle when the thread is normally under tension, whereby upon failure of the thread tensioning means to tension the thread, said first and second switches are simultaneously closed and said electro-magnet is energized, and a holding circuit connected across said source comprising in series said electro-magnet and said first and fourth switches, said electro-magnet when energized being adapted to close said fourth switch.

7. A sewing machine as defined in claim 6 comprising electrical signal means connected in parallel with said electro-magnet.

8. A machine as defined in'claim 6 comprising normally open switch means adapted to be closed by said mally closed reset switch in said holding circuit. 

1. The combination with a sewing machine having a reciprocable needle, drive means for cyclically reciprocating said needle, means to guide a thread from a Supply to the eye of the needle and means to tension the thread between the supply and needle during only a part of each cycle of operation of the needle, of control means for automatically rendering said drive means inoperable to reciprocate the needle upon failure of said thread tensioning means to tension the thread, said control means including a thread tension detector comprising a member having a first end adapted to be secured to a fixed support and an arm extending a substantial distance outwardly from said first end, means forming a first, fixed electrical contact affixed to said arm adjacent the outer end thereof, an electrically insulating body affixed to the first end of the member, an elongated electrically conducting coil spring extending generally parallel to and spaced from said arm, a first terminal means supported on the insulating body to which the first, inner end of the spring is secured, a thread guide secured to the second, outer end of the spring, and means affixed to the thread guide forming a second, movable contact which engages the first contact when the thread is untensioned, the thread guide being adapted to form a salient zone in the thread, whereby when the thread in said salient zone is subjected to appreciable tension the two contacts are separated.
 2. The combination as claimed in claim 1, wherein the first end of the member is generally in the form of a sleeve, the insulating body is a bushing mounted within the sleeve, the terminal means is a metal rod which extends through the bushing, and the first end of the spring is telescoped over and makes electrical connection with the outer end of the rod.
 3. The combination as claimed in claim 2, wherein the member is made of electrically conductive metal and is adapted to form a second terminal of the detector, and wherein the first contact is formed as a clip which is removably telescoped over the outer end of said arm.
 4. The combination of claim 1 including signal means and means for automatically energizing the signal means upon failure of said thread tensioning means to tension the thread.
 5. The combination of claim 1 wherein said control means functions, upon such failure, to effect stoppage of the needle at a predetermined approximate position in its cycle to facilitate rethreading thereof.
 6. In a sewing machine having a reciprocable needle, drive means for cyclically reciprocating said needle and means for tensioning a thread between a source and the needle, the combination therewith of an electrical control system comprising a source of electrical energy, a signal circuit connected across said source comprising a first normally closed switch, a second normally open switch, an electro-magnet and a third normally open switch adapted to be opened by said electro-magnet when the same is energized, said switches and electro-magnet being connected in series, a fourth normally open switch adapted to be closed by said electro-magnet when the same is energized, means for opening said first switch when the thread is under tension, means for momentarily closing the second switch during a portion only of each cycle of operation of the needle when the thread is normally under tension, whereby upon failure of the thread tensioning means to tension the thread, said first and second switches are simultaneously closed and said electro-magnet is energized, and a holding circuit connected across said source comprising in series said electro-magnet and said first and fourth switches, said electro-magnet when energized being adapted to close said fourth switch.
 7. A sewing machine as defined in claim 6 comprising electrical signal means connected in parallel with said electro-magnet.
 8. A machine as defined in claim 6 comprising normally open switch means adapted to be closed by said electro-magnet when the same is energized, another circuit connected across a source of electrical energy comprising in series a second electro-magnet, said normally open switch means and a normalLy open circuit breaker, means for momentarily closing said circuit breaker in synchronism with said second switch, whereby said second electro-magnet is energized following initial energization of said first-named electro-magnet, and normally closed switch means adapted to be opened by said second electro-magnet when the same is energized to de-energize said drive means.
 9. A machine as defined in claim 8 comprising a normally closed reset switch in said holding circuit. 